A novel catalyst, Fe3O4 nanoparticle decorated Al-Fe pillared bentonite (Fe3O4/Al-Fe-P-B), was prepared by in situ precipitation oxidization method. The catalyst was characterized by SEM, XRD and Raman spectroscopy. The Fe3O4 nanoparticles mainly exist on the surface or enter into the pore of bentonite, with better dispersing and less coaggregation. The catalytic activity of Fe3O4/Al-Fe-P-B was investigated in the degradation of Orange II (OII) by heterogeneous Fenton-like process. The effects of initial concentration of hydrogen peroxide, catalyst loading, temperature and initial pH on the degradation of OII were investigated. The Fe3O4/Al-Fe-P-B showed higher degradation efficiency of OII than bare Fe3O4 or Al-Fe-P-B in the degradation experiment. The enhanced catalytic activity of Fe3O4/Al-Fe-P-B in heterogeneous Fenton system was due to the synergistic effect between Al-Fe-P-B and Fe3O4. The novel catalyst can achieve solid-liquid separation easily by sample magnetic separation and has a good reusability and stability.